This topic describes differences in features and limits between enhanced NAT gateways and standard NAT gateways.

Comparison of features

Feature Enhanced NAT gateway Standard NAT gateway Reference
Multiple NAT gateways for one virtual private cloud (VPC) Supported Not supported Create a NAT gateway
Attach a NAT gateway to a vSwitch Supported Not supported
Billed on an hourly basis Supported Not supported Pay-as-you-go
Process TCP, UDP, and ICMP segments Supported Not supported N/A
Metric 22 4 Use Cloud Monitor to monitor NAT gateways
Network traffic monitoring (TOP ECS) Supported Not supported View monitoring data
Associate multiple elastic IP addresses (EIPs) with a NAT gateway Supported Supported Associate an EIP with a NAT gateway
SNAT Supported Supported Create a SNAT entry to access the Internet
Create multiple SNAT entries in a SNAT table Supported Supported Create a SNAT entry to access the Internet
Associate multiple EIPs with a SNAT table Supported Supported
DNAT Supported Supported Create a DNAT entry to provide Internet-facing services
DNAT port mapping Supported Supported Create a DNAT entry to provide Internet-facing services
DNAT IP mapping Supported Supported
Billed on a daily basis Not supported Supported Pay-as-you-go
ECS instances use SNAT to access services that use DNAT to provide external access when the same enhanced NAT gateway is used for SNAT and DNAT Not supported Supported Use SNAT of enhanced NAT gateways to enable ECS instances to access services that use DNAT to provide external access in the same VPC

Comparison of limits

Item Enhanced NAT gateway Standard NAT gateway
The maximum number of NAT gateways that can be created for a VPC 5. To increase the quota, submit a ticket. 1 (not adjustable)
Use an EIP for both SNAT and DNAT Only selected users can use an EIP for both SNAT and DNAT. To apply to be added to a whitelist, submit a ticket. Not supported (not adjustable)
The maximum number of DNAT entries that can be added to a NAT gateway 100. You can increase the quota. For more information, see Quota management. 100. You can increase the quota. For more information, see Quota management.
The maximum number of SNAT entries that can be added to a NAT gateway 40. You can increase the quota. For more information, see Quota management. 40. You can increase the quota. For more information, see Quota management.
The maximum number of EIPs that can be specified in a SNAT entry 64 (not adjustable) 64 (not adjustable)
Create a NAT gateway for a VPC that contains a custom route entry whose destination CIDR block is 0.0.0.0/0 Supported Not supported. You must delete the custom route entry whose destination CIDR block is 0.0.0.0/0 before you can create a NAT gateway for the VPC.
Limits on a vSwitch by the maximum bandwidth of the EIPs specified in the SNAT entry that is added to the vSwitch Yes. If the EIP is associated with an EIP bandwidth plan, the vSwitch is limited by the maximum bandwidth of the EIP bandwidth plan. Yes. If the EIP is associated with an EIP bandwidth plan, the vSwitch is limited by the maximum bandwidth of the EIP bandwidth plan.
The maximum number of EIPs that can be associated with a NAT gateway 20. You can increase the quota. For more information, see Quota management. 20. You can increase the quota. For more information, see Quota management.
The maximum number of pay-by-data-transfer EIPs that can be associated with a NAT gateway 10. You can increase the quota. For more information, see Quota management. 10. You can increase the quota. For more information, see Quota management.
The maximum bandwidth supported by a pay-by-data-transfer EIP that is associated with a NAT gateway 200 Mbit/s (not adjustable) 200 Mbit/s (not adjustable)
The maximum bandwidth of a NAT gateway 5 Gbit/s. If the total bandwidth of the EIPs or EIP bandwidth plans is greater than 5 Gbit/s, submit a ticket to increase the quota. A NAT gateway does not have a bandwidth limit. The bandwidth limit depends on the bandwidth of the EIPs that are specified in a SNAT entry or a DNAT entry, and the bandwidth of the EIP bandwidth plans to which the EIPs are added.

For example, you create a SNAT entry for a NAT gateway, and specify five pay-by-data-transfer EIPs and two pay-by-bandwidth EIPs with 500 Mbit/s bandwidth each in the SNAT entry. The bandwidth of the NAT gateway is limited to 2,000 Mbit/s. This value is based on the following calculation: 5 × 200 Mbit/s + 2 × 500 Mbit/s = 2,000 Mbit/s. If the seven EIPs are added to the same EIP bandwidth plan, and the bandwidth of the EIP bandwidth plan is limited to 1,000 Mbit/s, the bandwidth limit of the NAT gateway is 1,000 Mbit/s.

The maximum number of concurrent connections for an EIP is 55,000. Yes Yes
The maximum bandwidth of an EIP in an EIP bandwidth plan is 200 Mbit/s. No Yes
Users of NAT service plans are not allowed to associate EIPs with NAT gateways. Yes Yes
Transient connection errors may occur when you change the maximum bandwidth of the EIP bandwidth plan that is associated with a NAT gateway. For example, you can upgrade the maximum bandwidth from less than 1 Gbit/s to greater than 1 Gbit/s, or downgrade the maximum bandwidth from greater than 1 Gbit/s to less than 1 Gbit/s. No Yes
Transient connection errors may occur when IP addresses in the existing SNAT entries are reduced. Yes Yes
Transient connection errors may occur when IP addresses in the existing SNAT entries are increased. No Yes

References